Heat exchanger

ABSTRACT

A heat exchanger in one aspect of the present disclosure comprises a plurality of plates and a fin. The fin comprises at least one first portion and at least one second portion. The at least one first portion is a wall surface that comprises at least one first opening. The at least one second portion, which is paired with the first portion, is a wall surface different from the first portion. The second portion comprises a second opening paired with a corresponding one of the at least one first opening. The fin comprises at least one opening pair, which is a pair of the first opening and the second opening. The at least one opening pair has a non-overlapping positional relationship in which the paired first opening and second opening are at least partially non-overlapping along a flow direction of a second fluid.

CROSS-REFERENCE TO RELATED APPLICATION

This international application claims the benefit of Japanese Patent Application No. 2014-255334 filed on Dec. 17, 2014 with the Japan Patent Office, and the entire disclosure of Japanese Patent Application No. 2014-255334 is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a heat exchanger.

BACKGROUND ART

There has been known an exhaust heat recovery device that is provided with a heat exchanger to exchange heat between exhaust gas from an internal combustion engine as a high-temperature fluid and a low-temperature fluid, and recovers exhaust heat (see Patent Document 1 below). The heat exchanger described in Patent Document 1 is a stacked plate heat exchanger including a plurality of stacked plates having a flowing space through which the low-temperature fluid flows. The plate of the heat exchanger described in Patent Document 1 includes a convex portion projecting from an outer surface of the plate.

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: International Publication WO2014/014080

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

In the heat exchanger described in Patent Document 1, by providing a convex portion to the outer surface of the plate, a surface area of the outer surface of the plate is increased to thereby improve a heat exchange rate between the low-temperature fluid and the high-temperature fluid.

Generally, heat exchangers are required to achieve improvement in heat exchange rate from a high-temperature fluid to a low-temperature fluid, and a heat exchanger may be desired that achieves a greater heat exchange rate than that of the heat exchanger described in Patent Document 1.

Accordingly, in one aspect of the present disclosure, it is preferred to provide a heat exchanger allowing an improved heat exchange rate from a high-temperature fluid to a low-temperature fluid.

Means for Solving the Problems

One aspect of the present disclosure is a heat exchanger to exchange heat between a first fluid and a second fluid.

The heat exchanger comprises a plurality of plates and a fin.

The plurality of plates comprise a flow path through which the first fluid flows. The fin couples mutually adjacent plates among the plurality of plates. Also, the fin comprises at least one first portion and at least one second portion.

Of these portions, the first portion is a wall surface that comprises at least one first opening. The second portion is a wall surface that is paired with the first portion, and is different from the first portion. The second portion comprises a second opening paired with a corresponding one of the at least one first opening.

In the fin of the one aspect of the present disclosure, the paired first portion and second portion provide a wave-shaped section. Also, the fin is such that the first portion and the second portion each are arranged in a direction orthogonal to a flow direction of the second fluid. Further, the fin comprises at least one opening pair that is a pair of the first opening and the second opening. The at least one opening pair has a non-overlapping positional relationship in which the paired first opening and second opening are at least partially non-overlapping along the flow direction of the second fluid.

That is, the fin of the one aspect of the present disclosure extends such that the wall surfaces are orthogonal to the flow direction of the second fluid. Thus, the second fluid contacts the entire wall surfaces of the fin, and a large contact area can be obtained.

Further, in the one aspect of the present disclosure, the second fluid that has passed through the first opening of the fin strikes an area of the second portion facing the first opening. In the area of the second portion struck by the second fluid, a flow of the second fluid is disturbed; thus, it is possible to inhibit formation of a boundary layer in the area of the second portion struck by the second fluid. Accordingly, the heat exchanger of the one aspect of the present disclosure enables to inhibit formation of the boundary layer between the second fluid and the fin, and enables an efficient heat transfer from the second fluid to the first fluid.

In other words, the heat exchanger of the one aspect of the present disclosure enables further improvement in heat exchange rate from the high-temperature fluid to the low-temperature fluid.

The heat exchanger of the one aspect of the present disclosure may be configured as a heat exchanger in which cylindrical plates are stacked in an axial direction. In this case, the fin of one aspect of the present disclosure may be arranged along a circumferential direction of the plates.

In the aforementioned heat exchanger, the flow direction of the second fluid may be in a direction along a radial direction. Also, in the heat exchanger of the one aspect of the present disclosure, the first fluid flows along the circumferential direction of the plates. Thus, according to the heat exchanger of the one aspect of the present disclosure, the flow direction of the second fluid may be in a direction orthogonal to a flow direction of the first fluid. Further, according to the heat exchanger of the one aspect of the present disclosure, it is achieved that the flow direction of the second fluid is in a direction orthogonal to the flow direction of the first fluid over all radial directions of the plates, that is, over an entire flow area of the second fluid.

In the at least one opening pair of the heat exchanger of the one aspect of the present disclosure, the paired first opening and second opening may be entirely non-overlapping along the flow direction of the second fluid.

According to the aforementioned heat exchanger, a large area of the second portion can be struck by the second fluid that has passed through the first opening. Thus, the heat exchanger of the one aspect of the present disclosure enables to inhibit, over a larger area, formation of the boundary layer around a region of the second portion facing the first opening.

The fin in the heat exchanger of the one aspect of the present disclosure may be such that all the opening pairs each have a non-overlapping positional relationship.

According to the aforementioned heat exchanger, a much larger area of the second portion can be struck by the second fluid that has passed through the first opening. Thus, the heat exchanger of the one aspect of the present disclosure enables to inhibit, over a much larger area, formation of the boundary layer around a region of the second portion facing the first opening.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a schematic outer appearance of an exhaust heat recovery device in an embodiment.

FIG. 2 is a sectional view of the exhaust heat recovery device in a valve closed condition taken along a line II-II in FIG. 1.

FIG. 3 is a side view of a heat exchanger.

FIG. 4 is a perspective view showing an outer appearance of a plate and a fin.

FIG. 5 is a perspective view showing an outer appearance of the fin.

FIG. 6 is a top view of the fin.

EXPLANATION OF REFERENCE NUMERALS

1 . . . exhaust heat recovery device, 2 . . . exhaust portion, 4 . . . shell member, 6 . . . heat exchanging portion, 8 . . . inflow portion, 10 . . . valve, 12, 14 . . . exhaust pipe, 16 . . . upstream end, 18 . . . exhaust downstream end, 20 . . . outer shell member, 22 . . . lid member, 24 . . . retaining member, 28 . . . heat exchanging chamber, 30 . . . heat exchanger, 32 . . . plate, 34 . . . first plate portion, 36 . . . second plate portion, 38 . . . first communicating portion, 39 . . . second communicating portion, 40 . . . first cylindrical portion, 42 . . . second cylindrical portion, 44 . . . inflow pipe, 46 . . . outflow pipe, 50 . . . fin, 52 . . . first portion, 54 . . . second portion, 56 . . . first opening, 58 . . . first opening portion, 60 . . . second opening, 62 . . . second opening portion, 64, 66 . . . gap, 80 . . . introducing member, 102 . . . valve body, 104 . . . valve seat, 108 . . . mesh member, 110 . . . internal combustion engine, 112 . . . exhaust gas (second fluid), 114 . . . coolant (first fluid)

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment will be described as one example of the present disclosure with reference to the drawings.

<Exhaust Heat Recovery Device>

An exhaust heat recovery device 1 shown in FIG. 1 is mounted in a moving body that comprises an internal combustion engine 110. The exhaust heat recovery device 1 exchanges heat between exhaust gas 112 from the internal combustion engine 110 as a high-temperature fluid and a coolant 114 of the internal combustion engine 110 as a low-temperature fluid, to thereby recover heat from the exhaust gas 112. The exhaust gas 112 of the present embodiment is one example of “a second fluid” of the present disclosure, and the coolant 114 is one example of “a first fluid” of the present disclosure. The coolant 114 of the present embodiment may be cooling water or may be oil.

The exhaust heat recovery device 1 of the present embodiment comprises an exhaust portion 2, a shell member 4, a heat exchanging portion 6 (see FIG. 2), an inflow portion 8 (see FIG. 2), and a valve 10.

The exhaust portion 2 comprises a path to guide exhaust gas 112 from the internal combustion engine 110 toward downstream. The shell member 4 is a member covering an outside of the exhaust portion 2.

The heat exchanging portion 6 comprises a heat exchanger 30 (see FIG. 2) arranged between the exhaust portion 2 and the shell member 4, and performs heat exchange between the exhaust gas 112 as the high-temperature fluid and the low-temperature fluid that flows inside plates 32 of the heat exchanger 30.

The inflow portion 8 is a portion through which the exhaust gas 112 flows from the exhaust portion 2 into the heat exchanging portion 6. The valve 10, which is a known valve that opens and closes a path, is arranged downstream from the inflow portion 8 along a flow path of the exhaust gas 112 in the exhaust portion 2.

<Configuration of Exhaust Heat Recovery Device>

Next, a description will be given of a configuration of the exhaust heat recovery device 1.

As shown in FIG. 2, the exhaust portion 2 comprises an exhaust pipe 12.

The exhaust pipe 12 is a cylindrical member. The exhaust gas 112 from the internal combustion engine 110 flows into the exhaust pipe 12.

The shell member 4 comprises an exhaust pipe 14, an outer shell member 20, a lid member 22, and a retaining member 24.

The exhaust pipe 14 is a generally cylindrical member comprising an upstream end 16 as one end having an opening with an inner diameter greater than an outer diameter of the exhaust pipe 12. In an internal space of the exhaust pipe 14 at the upstream end 16, an exhaust downstream end 18, which is an end opposite to an upstream end, of the exhaust pipe 12 is arranged in a non-contact state with the shell member 4.

The outer shell member 20 is a cylindrical member with an inner diameter greater than a diameter of the exhaust pipe 12.

A downstream end of the outer shell member 20 is coupled to the upstream end 16 of the exhaust pipe 14.

The lid member 22 closes an upstream opening of the outer shell member 20 along the flow path of the exhaust gas 112 in the exhaust pipe 12.

In other words, the outer shell member 20, the lid member 22, and the exhaust pipe 12 provide a heat exchanging chamber 28 that is an annular space surrounded by the outer shell member 20, the lid member 22, and the exhaust pipe 12.

The heat exchanger 30 arranged in the heat exchanging chamber 28 is a heat exchanger, in which the coolant 114 flows and which is arranged so as to cover an outer circumference of the exhaust pipe 12.

<Configuration of Heat Exchanger>

As shown in FIG. 3, the heat exchanger 30 of the present embodiment comprises a plurality of plates 32-1 to 32-N, an inflow pipe 44, an outflow pipe 46, and a plurality of fins 50-1 to 50-M. That is, the heat exchanger 30 is a so-called stacked-plate heat exchanger.

Here, a symbol N, which is an identifier denoting the number of the plates 32, is a positive integer of 2 or more. Also, a symbol M in the present embodiment is an identifier denoting the number of the fins 50. The symbol M is, for example, a positive integer smaller by “1” than N.

Each of the plates 32 comprises a flow path through which the coolant 114 flows. The fin 50 couples mutually adjacent plates 32 among the plurality of plates 32. The inflow pipe 44 is a pipe to cause the coolant 114 from outside the heat exchanger 30 to flow into one plate 32. The outflow pipe 46 is a pipe to cause the coolant 114 to flow out of the heat exchanger 30 from one plate 32.

As shown in FIG. 4, each of the plates 32 comprises a first plate portion 34 and a second plate portion 36.

The first plate portion 34 is a ring-shaped member. The first plate portion 34 comprises a wall portion protruding in a same direction from a periphery of the first plate portion 34. The second plate portion 36 is a ring-shaped member. The second plate portion 36 comprises a wall portion protruding in a same direction from a periphery of the second plate portion 36.

Each of the plates 32 is formed by engaging the wall portion of the first plate portion 34 with the wall portion of the second plate portion 36. Each of the plates 32 comprises a gap between an inner surface of the first plate portion 34 and an inner surface of the second plate portion 36. The gap functions as a flowing space in which the low-temperature fluid flows, that is, a flow path of the coolant 114.

Each of the plates 32 comprises a first communicating portion 38 and a second communicating portion 39. Of these communicating portions, the first communicating portion 38 comprises a flow path through which the coolant 114 from the inflow pipe 44 flows into an adjacent plate 32 from upstream toward downstream along the flow path of the exhaust gas 112 in the exhaust portion 2. The second communicating portion 39 comprises a flow path through which the coolant 114 flows into an adjacent plate 32 from downstream to the outflow pipe 46 along the flow path of the exhaust gas 112 in the exhaust portion 2.

Each of the first communicating portion 38 and the second communicating portion 39 of the present embodiment comprises a first cylindrical portion 40 and a second cylindrical portion 42. The first cylindrical portion 40 is a cylindrical portion that is erected from an opening provided to the first plate portion 34 in a direction opposite to that of the wall portion. The second cylindrical portion 42 is a cylindrical portion that is erected from a periphery of an opening provided to the second plate portion 36 in a direction opposite to that of the wall portion.

When joined, the first cylindrical portions 40 provided to the first plate portion 34 and the second cylindrical portions 42 provided to the second plate portion 36 function as the first communicating portion 38 and the second communicating portion 39. The second cylindrical portion 42 provided to the second plate portion 36 here means the second cylindrical portion 42 provided to the second plate portion 36 that is adjacent to an outer surface of the first plate portion 34 through the fin 50.

A configuration method of the first communicating portion 38 and the second communicating portion 39 is not limited to this, and any configuration may be employed in which these portions are configured to function as a flow path for the coolant 114 through the plates 32.

Each of the plates 32 is also arranged so as to cover the outer circumference of the exhaust pipe 12. Each of the plates 32 is arranged so as to have a gap 64 between a center side periphery of the plate 32 in a radial direction thereof and an outer surface of the exhaust pipe 12, the gap 64 being located along a radial direction of the exhaust pipe 12. Also, each of the plates 32 is arranged so as to have a gap 66 between an outer side periphery of the plate 32 in the radial direction thereof and an inner surface of the outer shell member 20, the gap 66 being located along the radial direction of the exhaust pipe 12.

With this configuration, the exhaust gas 112 in the present embodiment flows in a direction from the outer surface of the exhaust pipe 12 toward the inner surface of the outer shell member 20 along a radial direction of the plate 32.

The fin 50 is a truncated arc member coupled to two plates 32 adjacent to each other. As shown in FIG. 5 and FIG. 6, the fin 50 comprises first portions 52-1 to 52-L and second portions 54-1 to 54-L. In the fin 50, the first portions 52 and the second portions 54 are coupled, to thereby provide a triangular wave-shaped section of the fin 50 in its entirety. A symbol “L” here is an integer of 1 or more.

The first portions 52 are each a rectangular plate portion that functions as a wall surface of the fin 50. The first portions 52 each comprise at least one first opening portion 58 having a first opening 56. In the present embodiment, the first portions 52 each may have the first openings 56 arranged at equal intervals, or may have the first openings 56 arranged at unequal intervals.

The second portions 54 are each a rectangular plate portion that is paired with the first portion 52 and functions as a wall surface different from the first portion 52. Also, the second portions 54 each comprise at least one second opening portion 62 having a second opening 60 that is paired with the first opening 56. In the present embodiment, the second portions each may have the second openings 60 arranged at equal intervals, or may have the second openings 60 arranged at unequal intervals.

Areas of the individual first openings 56, areas of the individual second openings 60, a total area of the first openings 56, and a total area of the second openings 60 may be appropriately determined in consideration of a pressure of the exhaust gas 112.

One side in a longitudinal direction of one of the first portions 52 is coupled to one side in a longitudinal direction of one of the second portions 54. The other side in the longitudinal direction of the one of the first portions 52 is coupled to one side in a longitudinal direction of a different one of the second portions 54. With the aforementioned configuration, the triangular wave-shaped section of the fin 50 in its entirety is provided.

Further, the fin 50 is coupled to the plate 32 such that an arc of the fin 50 is arranged along a circumferential direction of the plate 32. Specifically, in the fin 50, peaks on one side of the triangular wave shape are coupled to an outer surface of one of the plates 32. Remaining peaks of the triangular wave shape are coupled to an outer surface of another one of the plates 32 adjacent to the one of the plates 32. With this configuration, in the present embodiment, the first portions 52 and the second portions 54 are each arranged in a direction orthogonal to the flow direction of the exhaust gas 112.

The individual first portions 52 may have the same number of the first openings 56 regardless of locations of the individual first portions 52 in a radial direction, or may have a larger number of the first openings 56 as the first portion 52 is located closer to an outer periphery. Also, it is preferred that the number of the second openings 60 provided to one of the second portions 54 be the same as the number of the first openings 56 provided to the first portion 52 corresponding to the one of the second portions 54.

In the fin 50, among opening pairs 70, each of which is a pair of the first opening 56 and the second opening 60, the first opening 56 and the second opening 60 forming at least one of the opening pairs 70 are at least partially non-overlapping, that is, in a non-overlapping positional relationship along the flow direction of the exhaust gas 112.

The opening pair 70 herein means a pair of the first opening 56 and the second opening 60, the second opening 60 satisfying a specified condition, among the first openings 56 and the second openings 60 provided to an individual pair of the first portion 52 and the second portion 54. The specified condition herein may be that the second opening 60 is located nearest to the first opening 56, or may be another condition.

The non-overlapping positional relationship in the present embodiment specifically means that the second opening 60 is entirely non-overlapping with the paired first opening 56 in the opening pair 70 in a normal direction of the first portion 52. The non-overlapping positional relationship includes, for example, a relationship in which the second openings 60 and the first openings 56 are arranged zigzag. In the present embodiment, a positional relationship between the first opening 56 and the second opening 60 forming each of the opening pairs 70 is the non-overlapping positional relationship.

In the present embodiment, the gap 64, the first openings 56, the second openings 60, and the gap 66 function as the flow path of the exhaust gas 112.

Heat exchange is performed between the high-temperature fluid (a second fluid), which is the exhaust gas 112 flowing through the gap 64, the first openings 56, the second openings 60, and the gap 66, and the low-temperature fluid (a first fluid), which is the coolant 114 flowing through each of the plates 32. That is, in the present embodiment, the heat exchanging chamber 28 in which the heat exchanger 30 is arranged functions as the heat exchanging portion 6.

The retaining member 24 shown in FIG. 2 is a member to retain the heat exchanger 30 arranged in the heat exchanging chamber 28.

An introducing member 80 is a cylindrical member having a diameter larger than that of the exhaust pipe 12 and having one end coupled to the retaining member 24. The other end of the introducing member 80 opposite to the one end coupled to the retaining member 24 has a diffuser shape with a gradually increasing diameter.

The introducing member 80 is arranged to provide an opening between the introducing member 80 and the exhaust pipe 12. The opening functions as an inflow port for the exhaust gas 112 into the heat exchanging portion 6.

The valve 10, which comprises at least a valve body 102 and a valve seat 104, closes the exhaust portion 2 (the introducing member 80) by contact of the valve body 102 with the valve seat 104. In the present embodiment, the diffuser shaped end of the introducing member 80 functions as the valve seat 104. The valve seat 104 of the present disclosure, however, is not limited to this configuration, but a dedicated member may alternatively be provided.

A mesh member 108 having a meshed configuration is attached to an inner circumferential surface of the valve seat 104.

The valve 10 of the present embodiment opens the exhaust portion 2 when a coolant temperature of the coolant 114 in the internal combustion engine 110 is higher than a specified temperature that is previously determined. On the other hand, the valve 10 closes the exhaust portion 2 when the coolant temperature of the coolant 114 in the internal combustion engine 110 is lower than the specified temperature.

<Operation and Effects of Exhaust Heat Recovery Device>

When the valve 10 is closed to thereby close the exhaust portion 2 in the exhaust heat recovery device 1, the exhaust gas 112 from the internal combustion engine 110 flows through the inflow portion 8 into the heat exchanging portion 6, and heat exchange with the coolant 114 is performed in the heat exchanging portion 6.

The fins 50 provided to the heat exchanger 30 extend such that the wall surfaces are orthogonal to the flow direction of the exhaust gas 112. Thus, the exhaust gas 112 contact the entire wall surfaces of the fins 50. Accordingly, a large contact area between the fins 50 and the exhaust gas 112 can be ensured, and a more efficient heat transfer from the exhaust gas 112 to the coolant 114 can be achieved.

Also, the exhaust gas 112 that has passed through the first opening 56 of the fin 50 strikes a region, which faces the first opening 56, of the second portion 54. In the area of the second portion 54 struck by the exhaust gas 112, the flow of the exhaust gas 112 is disturbed; thus, it is possible to inhibit formation of a boundary layer in the region of the second portion 54 struck by the exhaust gas 112. Accordingly, the heat exchanger 30 enables an efficient heat transfer between the exhaust gas 112 flowing between the plates 32 and the coolant 114 flowing through the plates 32.

Particularly, in the present embodiment, the first opening 56 and the second opening 60 paired as the at least one opening pair 70 are entirely non-overlapping along the flow direction of the exhaust gas 112, and also all of the opening pairs 70 are in the non-overlapping positional relationship.

Thus, the heat exchanger 30 enables to increase the area of the second portion 54 to be struck by the exhaust gas 112 that has passed through the first openings 56. According to the heat exchanger 30, therefore, formation of a boundary layer can be inhibited in a larger area.

As described above, the heat exchanger 30 enables further improvement in heat exchange rate from the high-temperature fluid to the low-temperature fluid.

Also, the cylindrical plates 32 are stacked in an axial direction in the heat exchanger 30. The fins 50 are arranged so as to have their arcs located along the circumferential direction of the plates 32.

Accordingly, the heat exchanger 30 enables to orient the flow direction of the exhaust gas 112 to a direction along the radial direction of the plates 32. Also, in the heat exchanger 30 with this configuration, the coolant 114 flows along the circumferential direction of the plates 32. Thus, the heat exchanger 30 enables to orient the flow direction of the exhaust gas 112 to a direction orthogonal to the flow direction of the coolant 114. Further, the heat exchanger 30 enables to orient the flow direction of the exhaust gas 112 to a direction orthogonal to the flow direction of the coolant 114 in all radial directions of the plates 32.

[Other Embodiments]

Although the embodiment of the present disclosure has been described above, the present disclosure is not limited to the aforementioned embodiment, but may be practiced in various forms within the scope not departing from the spirit of the present disclosure.

For example, although the sectional shape of the fin 50 in its entirety is a triangular wave shape in the aforementioned embodiment, the sectional shape of the fin 50 is not limited to this shape, but may be a sine wave shape, a rectangular wave shape, or a saw-tooth wave shape. That is, the fin 50 may have any sectional shape if the sectional shape of the fin 50 in its entirety is a wave shape.

Also, in the aforementioned embodiment, the non-overlapping positional relationship is defined that the first opening 56 and the second opening 60 forming the at least one opening pair 70 are entirely non-overlapping along the flow direction of the exhaust gas 112; however, the non-overlapping positional relationship is not limited to this relationship, but may be a relationship where the first opening 56 and the second opening 60 forming the at least one opening pair 70 are at least partially non-overlapping.

Further, in the aforementioned embodiment, all of the opening pairs 70 are each the opening pair 70 having the non-overlapping positional relationship; however, at least one of the opening pairs 70 may be the opening pair 70 having the non-overlapping positional relationship according to the present disclosure.

In the aforementioned embodiment, the opening between the exhaust downstream end 18 and the introducing member 88 functions as the inflow port for exhaust gas 142 from the exhaust pipe 12 to the heat exchanging portion 6; however, the inflow port for exhaust gas 142 from the exhaust pipe 12 to the heat exchanging portion 6 may be holes bored in the exhaust pipe 12 itself.

Moreover, the exhaust heat recovery device 1 of the aforementioned embodiment is mounted to a moving body that comprises the internal combustion engine 110; however, the exhaust heat recovery device of the present disclosure is not required to be mounted to a moving body. That is, the exhaust heat recovery device in the present disclosure, which is configured to recover heat from the exhaust gas 112 by heat exchange using the exhaust gas 112 from the internal combustion engine 110 as the high-temperature fluid, may be used without being mounted to a moving body. Also, the low-temperature fluid in the exhaust heat recovery device is not limited to the coolant 114, but may be any other fluid that functions as a low-temperature fluid.

Although the heat exchanger 30 is applied to the exhaust heat recovery device 1 in the aforementioned embodiment, the heat exchanger 30 may be applicable to devices other than the exhaust heat recovery device 1.

Also, the shape of the heat exchanger 30 is not limited to a cylindrical shape. Specifically, in the heat exchanger of the present disclosure, the plates 32 and the fins each may have a rectangular shape or any other shape on condition that the fins 50 coupling the adjacent plates 32 are provided so as to be orthogonal to the flow direction of the second fluid.

Any form in which part of a configuration in the aforementioned embodiment is omitted may be an embodiment of the present disclosure. Also, any form in which the aforementioned embodiment and a modified example are appropriately combined may be an embodiment of the present disclosure. Further, any form that can be conceived within the scope not departing from the essence of the present disclosure defined by the language of the claims may be an embodiment of the present disclosure. 

1. A heat exchanger to exchange heat between a first fluid and a second fluid, the heat exchanger comprising: a plurality of plates comprising a flow path through which the first fluid flows; and a fin configured to couple mutually adjacent plates among the plurality of plates, wherein the fin comprises: at least one first portion that is a wall surface and comprises at least one first opening; at least one second portion that is a wall surface paired with the first portion and is different from the first portion, the at least one second portion comprising a second opening paired with a corresponding one of the at least one first opening, the paired first portion and second portion providing a wave-shaped section, and the first portion and the second portion each being arranged in a direction orthogonal to a flow direction of the second fluid; and at least one opening pair that is a pair of the first opening and the second opening, the at least one opening pair having a non-overlapping positional relationship in which the paired first opening and second opening are at least partially non-overlapping along the flow direction of the second fluid.
 2. The heat exchanger according to claim 1, wherein each of the plurality of plates has a cylindrical shape, wherein the plurality of plates are arranged along an axial direction, and wherein the fin is arranged along a circumferential direction of the plates.
 3. The heat exchanger according to claim 1, wherein the at least one opening pair is such that the paired first opening and second opening are entirely non-overlapping along the flow direction of the second fluid.
 4. The heat exchanger according to claim 1, wherein the fin is such that each of the opening pair has the non-overlapping positional relationship.
 5. The heat exchanger according to claim 2, wherein the at least one opening pair is such that the paired first opening and second opening are entirely non-overlapping along the flow direction of the second fluid.
 6. The heat exchanger according to claim 2, wherein the fin is such that each of the opening pair has the non-overlapping positional relationship.
 7. The heat exchanger according to claim 3, wherein the fin is such that each of the opening pair has the non-overlapping positional relationship. 